Silver development in microscopy and bioanalysis: Past and present

Geoffrey R. Newman, Bharat Jasani

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

With the experience accumulated from more than a century of silver applications in biology and medicine, physical development has become a powerful bioanalytical tool for marker amplification in blotting procedures, in situ hybridization, immunocytochemistry, histochemistry, and cytochemistry. Early, empirical techniques of silver impregnation followed by development in a reducing solution (chemical developer), or a solution which contained both silver reducers and silver salts (physical developer) were often capricious and suffered from unwanted silver precipitation caused by light and self-nucleation. To accommodate the modern demand for accurate physical development, various strategies have been devised to counter these problems. One approach has been to introduce organic colloids into the developer to keep the silver ions and reducer molecules apart, whilst excluding light by using a dark-room or by covering the solution. Albumen, gelatin, and complex polysaccharides have all been tested, but gum arabic is preferred. In addition, further control can be achieved by slowing down the rate of development with low pH and by changing from silver nitrate to silver lactate, which dissociates more slowly. Effective colloid protection in a physical developer is also provided by the inclusion of tungsten salts which can delay light-catalysed silver reduction and keep the developer clear for many minutes. The same result has been achieved by complexing the silver salt in the physical developer with very large organic molecules, restricting ionization. 'Light insensitive' commercial designer products have resulted. Probably no single formulation can satisfy all conditions of use, but with increased understanding of the mechanisms of physical developers a more flexible, user-friendly approach is anticipated.

Original languageEnglish
Pages (from-to)119-125
Number of pages7
JournalJournal of Pathology
Volume186
Issue number2
DOIs
Publication statusPublished - Oct 1998
Externally publishedYes

Fingerprint

Silver
Microscopy
Light
Salts
Colloids
Gum Arabic
Silver Nitrate
Physical and Rehabilitation Medicine
Histocytochemistry
Tungsten
Gelatin
In Situ Hybridization
Polysaccharides
Lactic Acid
Immunohistochemistry
Ions

Keywords

  • Bioanalysis
  • Colloidal gold
  • Diaminobenzidine
  • Physical developer
  • Silver

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Cite this

Silver development in microscopy and bioanalysis : Past and present. / Newman, Geoffrey R.; Jasani, Bharat.

In: Journal of Pathology, Vol. 186, No. 2, 10.1998, p. 119-125.

Research output: Contribution to journalArticle

Newman, Geoffrey R. ; Jasani, Bharat. / Silver development in microscopy and bioanalysis : Past and present. In: Journal of Pathology. 1998 ; Vol. 186, No. 2. pp. 119-125.
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